Add Maximum Subarray in C# (TheRenegadeCoder#4877)

Author: pascalecu

archive/c/c-sharp/MaximumSubarray.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+public static class Program
+{
+    private static void ShowUsage()
+    {
+        Console.Error.WriteLine("Usage: Please provide a list of integers in the format: \"1, 2, 3, 4, 5\"");
+        Environment.Exit(1);
+    }
+
+    private static List<int> ParseIntegerList(string input)
+    {
+        if (string.IsNullOrWhiteSpace(input))
+            ShowUsage();
+
+        var list = input
+            .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
+            .Select(s =>
+            {
+                if (!int.TryParse(s, out var val))
+                    ShowUsage();
+                return val;
+            })
+            .ToList();
+
+        if (list.Count == 0)
+            ShowUsage();
+
+        return list;
+    }
+
+    private static int MaximumSubarraySum(IReadOnlyList<int> numbers)
+    {
+        if (numbers.Count == 0)
+            return 0;
+
+        int currentSum = numbers[0];
+        int maxSum = numbers[0];
+
+        for (int i = 1; i < numbers.Count; i++)
+        {
+            int number = numbers[i];
+            currentSum = Math.Max(number, currentSum + number);
+            maxSum = Math.Max(maxSum, currentSum);
+        }
+
+        return maxSum;
+    }
+
+    public static int Main(string[] args)
+    {
+        if (args.Length != 1)
+            ShowUsage();
+
+        var inputList = ParseIntegerList(args[0]);
+
+        Console.WriteLine(MaximumSubarraySum(inputList));
+
+        return 0;
+    }
+}